Integrated circuit technology now requires, more than ever, high density packaging in a flexible form to accommodate portability. Spatial and weight constraints associated with consumer electronics, such as notebook computers, pagers and cellular phones, require fewer interconnections between devices in exchange for greater integration.
Most integrated circuits are formed on semiconductor wafers and mounted using chip carriers or packages onto printed circuit boards. Another area of interest has been on techniques to improve device density by forming what are commonly known as multi-chip modules (MCMs). In a multi-chip module, one high density device makes connection to another upon a common substrate.
A further area of interest has been on techniques to lay passive components as well as, integrated circuits on flexible material resulting in so called "flexible circuits". Also, the combined technique of fabricating MCMs placed on flexible material has been the subject of research activity. These devices to date, however, merely include discrete non-flexible circuits on a flexible support material or simply wires on or within a flexible material referred to generally as "flex cable". Circuit elements that can undergo flexible movement have been limited to metal interconnect devices.
Presently, there is a continuing need to improve the fabrication process for circuits to accommodate more complex electronic systems which require active circuit elements in a significantly reduced size.